I just got my qmail to work within my domain. But when I try to send emails to my yahoo account it doesnt work. My "/var/log/qmail/qmail-send/current" says:

@400000004446a23022d9499c new msg 1130595
@400000004446a23022d9516c info msg 1130595: bytes 382 from <root@mydomain.net> qp 8687 uid 0
@400000004446a230239e474c starting delivery 7: msg 1130595 to remote someone@yahoo.com
@400000004446a230239e4f1c status: local 0/10 remote 2/20
@400000004446a2e4308184c4 delivery 7: deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/
@400000004446a2e43081907c status: local 0/10 remote 1/20

I changed my info to mydomain and my email address. Why dont I have an SMTP connection? Do I need to open ports in my router (I am behind a router) for my server to be able to send/receive messages? I also tried the other way (sending a message from yahoo to my mail server) w/o success too.

Is there any other log/file that I need to display here to help track the problem? Can anyone help me? Thanks in advance.

I just realized that I had to open port 25 on my router and forward it to the server. That done I tested the connection with telnet and managed to get thru. I still get the same problem. Maybe a problem w/ mysql db?
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EDITED:
I just got the test emails I sent to my server from my yahoo account 4 hours ago. But still no outgoing mail from the server. Can anyone help me with this?

Now I start to believe there is something wrong with my vpopmail setup. I continue following the guide as in:
http://www.gentoo.org/doc/en/qmail-howto.xml

And just now I tried:
zeus# vadddomain mymachine.homelinux.net postpass
vmysql: error creating table 'dir_control': MySQL server has gone away
vmysql: sql error[b]: MySQL server has gone away
vmysql: sql error[3]: MySQL server has gone away
vmysql: error creating table 'limits': MySQL server has gone away
vmysql: sql error[p]: MySQL server has gone away
Error: (vadduser) can't read domain limits
zeus# vadduser john@mymachine.homelinux.net
Please enter password for john@mymachine.homelinux.net:
enter password again:
vmysql: error creating table 'limits': MySQL server has gone away
vmysql: sql error[p]: MySQL server has gone away
Error: can't read domain limits
zeus# /etc/init.d/mysql status
* status: started

I understand from the messages that mysql is down, but it is actually running. What can be wrong? can anyone help?

HA! I just restarted the server and all of a sudden I cant send receive emails anymore! It misteriously append my domain name to the beggining of the destination mail, this sample is a msg sent by cron to the root account(it was working fine before the reset):

@400000004447fc9c38a4b5a4 starting delivery 11: msg 1130653 to local mydomain.homelinux.net-root@mydomain.homelinux.net
@400000004447fc9c391e9cac delivery 11: deferral: vdelivermail:_deferred,_database_down/

I removed it from my system and I am going to reinstall it all over again. Hope I get it right this time.

try http://shupp.org/toaster/

It didnt work. I tried some of the suggestions like the relay addresses but nothing so far. All I can do is send local email and receive email from other domains. I will continue working on this until I solve it or someone give me a hint to solve it. Thanks for your suggestion! Have any others?

I found out that my ISP blocked my outgoing port 25 for secutiry purposes. I asked them to open it for me and now my email server is rocking! Thanks guys for your help.

But (there is always a but) I still have one problem. When I send an email using mutt my hostname is appended to my domain name and I get an invalid return recipient. How can I fix that? An example:
I want my email to be:
myself@mydomain.net

my hostname (my server's name) is: servername

when i send an email w/ qmail-inject i get my return email as myself@mydomain.net

when i send an email w/ mutt i get my return email as myself@myservername.mydomain.net

Does any one knows why that happen?

Thanks!
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EDITED: I just found a temporary solution: I added a file .muttrc like this to my user home
set hostname=mydomain.net

And it works as desired now.